--- /n/sources/plan9/sys/src/9/ip/tcp.c Thu Mar 6 01:52:18 2014 +++ /sys/src/9/ip/tcp.c Sun Feb 28 00:00:00 2016 @@ -1774,11 +1774,13 @@ tcb->flgcnt = 0; tcb->flags |= SYNACK; + /* set desired mss and scale */ + tcb->mss = tcpmtu(s->p, dst, s->ipversion, &tcb->scale); + /* our sending max segment size cannot be bigger than what he asked for */ - if(lp->mss != 0 && lp->mss < tcb->mss) { + if(lp->mss != 0 && lp->mss < tcb->mss) tcb->mss = lp->mss; - tpriv->stats[Mss] = tcb->mss; - } + tpriv->stats[Mss] = tcb->mss; /* window scaling */ tcpsetscale(new, tcb, lp->rcvscale, lp->sndscale);